1=================== 2Switching Scheduler 3=================== 4 5Each io queue has a set of io scheduler tunables associated with it. These 6tunables control how the io scheduler works. You can find these entries 7in:: 8 9 /sys/block/<device>/queue/iosched 10 11assuming that you have sysfs mounted on /sys. If you don't have sysfs mounted, 12you can do so by typing:: 13 14 # mount none /sys -t sysfs 15 16It is possible to change the IO scheduler for a given block device on 17the fly to select one of mq-deadline, none, bfq, or kyber schedulers - 18which can improve that device's throughput. 19 20To set a specific scheduler, simply do this:: 21 22 echo SCHEDNAME > /sys/block/DEV/queue/scheduler 23 24where SCHEDNAME is the name of a defined IO scheduler, and DEV is the 25device name (hda, hdb, sga, or whatever you happen to have). 26 27The list of defined schedulers can be found by simply doing 28a "cat /sys/block/DEV/queue/scheduler" - the list of valid names 29will be displayed, with the currently selected scheduler in brackets:: 30 31 # cat /sys/block/sda/queue/scheduler 32 [mq-deadline] kyber bfq none 33 # echo none >/sys/block/sda/queue/scheduler 34 # cat /sys/block/sda/queue/scheduler 35 [none] mq-deadline kyber bfq 36